Palms and Cycads: Palm fronds turning BLACK?!?!

I have this Majesty Palm tree planted in my yard. It's never looked real healthy, but recently, I noticed this black, tar looking stuff growing on one of the main fronds. Seems to be isolated to the east facing side of the stem. Tree gets 6-8 hours of direct sun everyday.

Anyone seen this before? If so, please advise what it is and how to treat it if known.